Improvement in steam-engine cut-offs



dilated '5ta-tra SAMUEL DUNBAR, or ANEW YORK, N. Y.

Letters Patent No. 90,643, dated .Tune 1, 18.69.

IMPROVEMENT IN STEAM-ENGINE CUT-CPFS.

The Schedule referred to in these Letten Patent end making part of the saine.

To all whom it may concern:

Be it known that I, SAMUEL DUNBAR, of' New York, in the 'county of New York, and State oi New York, have invented a new and useful ValveGear for Steam-Engines; and I do hereby declare that the following is a full, clear, and exact description thereof', reference being had to the accompanying drawings, making part of this specification, and to the letters of reference marked thereon.

The nature of my invention consists in the construction and arrangement of' parts, hereinafter fully described, for operating the valves of' steam-engines, which may be so adjustedas to admit any desired quantity of steam to the cylinder, ,at the will of the attendant.

To enable those skilled in the art to which my in-v vention appertains, to make and use the same, I will proceed to describe its construction and operation.4

In the drawings- Figure l is an end view ofthe ange D of' the sleeve B, showing the steel toe G, attached thereto.

FigureZ is an elevation of"""the sleeve B, with its anges D and C, and driving-shaft A.

v Figure 3 is a view of' the fiange C of the sleeveY B, showing the end of the movable toe H.

Figure 4 shows a device for operating the cam I, by means of a governor.

Figure 5 shows the movable toe H.

Figure 6 is a side view of the yoke E.

Figure 7 is a side elevation of the improvement as it would appear whenl put together.

Figure 8 is a side view of the-yoke F.

Figure 9 is a view of the camI.: y

Figure 10 shows the device for operating the cam I by band. r

- The driving-shaft A, as shown in gs. 2 and 7, is

the engine.

On the shaft A, I secure the sleeve B, with its fanges D and C, and on the flange D, I 'secure the steel toe G, by means of a screw, or otherwise, as

. shown in fig. 1.

In the auge C, I make a cavity, suciently deep to receive, flush with its face, the steel t-oe H, aslshown in gs. 2 and 3.

The toe H has a shank forged upon it, the end of which rests in the fiange D.

On this shank I place a spiral spring, as shown in iig. 7, the eiect of which is to keep the toe Hin contact with the face or" the cam I, which is placed on the shaft A.

The yokes E and F are made of steel, and are placed in a vertical position, the shaft A passing through them, as shown in fig. 7. The yoke E is attached to the exhaust-valve, and the yoke F to the inlet-valve.

When the engine is in motion, the exhaust-valve is raised and dropped by means of the toe G, on the fiange D, coming in contact with that part of the yoke E marked a b, and it is kept open as long as it is in contact with said surface.

The inlet-valve is raised by means of' the movable toe H coming in contact with that part of' the yoke F marked c d, and the time it is kept open depends on the position of the cam I, said cam being loose on the shaft A, and is actuated by means of the lever J, as shown in fig. 10, or by means of the segment-gear and rack K, as shown in iig. 4, which maybe attached to and actuated by a governor.

The advantage of my improvement is, that it may I be entirely under the control of' the attendant, who

may, at his option, canse the steam to follow the entire length of the stroke, or to cut it off at any desired point. The motion of the engine can also be reversed at tne will of the operator, or it can be made automatic by means of the governor.

Having thus described my invention,

What I claim as new, and desire to securehby Letters Patent, is-

1. The yokes E and F, when constructed substantially as shown and described.

2. The combination of the yokes E and F with the toes G and H, when constructed substantially as shown and described.

3. The cam I and yoke F, when constructed as shown and described.

4. The cam I and lever J, when constructed and arranged to operate as shown and described.

SAML. DUNBAR.

Witnesses:

E. R. BROWN,

G. A. G. SMITH. 

